Larry and Palmerston square off against each other and fight in Downing Street in London, July 17, 2016. [Photo/sipaphoto.com]

The simmering feud between Larry, the Downing Street's tabby, and Palmerston, the Foreign Office's feline, shows no sign of abating.

Larry made a triumphant return to the corridors of power this week after their latest fight.

Palmerston tried to sneak into the Prime Minister's home on Tuesday, but the cat was spotted by a security guard who quickly grabbed him and dumped him outside on the pavement.

Palmerston then came face to face with Larry and the pair had a small stand-off.

Larry has been involved in scuffles in the street with Palmerston in recent weeks. One of these fights is thought to have resulted in Larry getting an injured right front paw, which required veterinary treatment.

No 10 Downing Street, the home of British Prime Minister Theresa May, is just across the street from the UK's Foreign Office.

Larry arrived in 2011 to take care of the mouse problem at the prime minister's residence. Palmerston, however, is a newcomer, having arrived in April.